1. Field of the Invention
This present invention relates generally to the repair of integrated microcircuit assemblies. More particularly, the present invention relates to a method and device for connecting a replacement lead to an integrated microcircuit housing.
2. Discussion of the Related Art
Integrated microcircuit assemblies typically include one or more microcircuits packaged inside a housing made of a material such as ceramic or plastic. The housing generally has a number of conductive elements providing a conductive pathway through the housing for attachment of leads to the microcircuit. For example, if the housing is made of a ceramic material, the conductive element will often be a via. Similarly, if the housing is made of a plastic material, the conductive element is generally an internal lead frame. In any case, under conventional approaches the leads are electrically connected to the conductive elements and provide a mechanism for connecting the microcircuit assembly to other circuits, systems, and components.
The above-described leads are attached to and/or exit the housing at various angles and configurations, which causes them to be subjected to varying amounts of stress. This stress, or repeated applications of stress, can cause the leads to break off in such a way that makes the microcircuit assemblies very difficult to repair. Commonly, the entire integrated microcircuit assembly is discarded and replaced with one having all leads intact. It is easy to understand that this approach results in increased part costs and production delays. It is therefore desirable to provide a method and device for repairing broken or missing leads of integrated microcircuit assemblies.
Another approach to correcting for broken or missing leads involves replacing the entire housing. This therefore requires removal of the microcircuit or microcircuits from the housing and the insertion of the microcircuits into a new housing. This approach, however, can be labor intensive and generally results in higher manufacturing costs. There is also an increased potential for damaging the microcircuit during either the removal or replacement process. It is therefore desirable to provide a method and device for repairing broken or missing leads of integrated microcircuit assemblies that does not involve replacing the entire housing.
Other conventional approaches involve soldering the broken lead, or a replacement lead, back onto the conductive element. This approach is not always possible, however, due to metallurgy incompatibilities. Even in cases where a lead can be replaced by soldering, it is often very difficult to perform subsequent operations with the integrated circuit assembly because leads attached with solder will often fall off when subjected to heat. Thus, in subsequent soldering applications associated with connecting the integrated microcircuit assembly with other circuits, systems, and components, the replacement lead will often fall off again. This also adds to manufacturing costs and reduces reliability. It is therefore desirable to provide a method and device for connecting a replacement lead to an integrated microcircuit housing that does not involve the above-described soldering process. It is also desirable to provide mechanical reinforcement to the replacement lead so that reliability is improved and manufacturing costs are reduced.
The above and other objectives are achieved by a method and device in accordance with the present invention for replacing broken or missing integrated microcircuit assembly leads. The method includes the step of providing the replacement lead, where the replacement lead has an attachment end. The attachment end of the replacement lead is welded to an enhancement device, where the enhancement device has a larger contact surface area than the attachment end of the replacement lead. The method further includes the step of attaching the enhancement device to the housing such that the contact surface area of the enhancement device provides mechanical reinforcement to the replacement lead.
Further in accordance with the present invention, a method for attaching a replacement lead enhancement device to an integrated microcircuit housing is provided. The method includes the step of etching an attachment region out of the housing, where the attachment region is located adjacent to a conductive element of the housing. The conductive element provides a conductive pathway through the housing. The enhancement device is then aligned with the attachment region, and bonded to the conductive element with an electrically conductive adhesive.
In another aspect of the invention, a replacement lead assembly for an integrated microcircuit housing includes a replacement lead, and an enhancement device. The enhancement device is welded to an attachment end of the replacement lead. The enhancement device has a larger contact surface area than the attachment end of the replacement lead.